This health services study, responding to PA-07-066: Alcohol Use Disorders: Treatment, Services Research, and Recovery (RO1), proposes to study the long-term trajectories of alcohol use, related social outcomes, service use and cost in a clinical cohort of young adults. This is a secondary analysis of a sample (N=419) of adolescents who entered chemical dependency (CD) treatment in a private managed care health plan between 2000 and 2002. Follow-up data are available at 6 months, 1, 3, 5, and 7 years, and we are currently collecting 9-year data with support from NIAAA supplemental funds and Kaiser Permanente's Division of Research. With the 9 year data, the full sample (aged 13-18 years at baseline, aged 22-27 years for the proposed study) will have been measured during the important maturation period of adolescence to young adulthood. Few longitudinal studies have examined treatment samples through this developmental period with this long of a follow-up. By 9 years, the study sample has had the time to experience significant life transitions (i.e. marriage, parenthood), and the role of these transitions may be different for a treatment sample compared to general population samples. The study addresses significant gaps in the literature: We examine the role of health services on long-term outcomes, which the trajectories literature has not done. We propose an innovative approach to examine the impact of health services use by defining and testing a model of Continuing Care that includes a combination of primary care (PC) and specialty CD/mental health services using a disease-management approach. We also examine trajectories of long-term medical services and costs, which have also not been examined. Finally, we study lack of insurance on long-term outcomes and service use/costs in this vulnerable group with a history of alcohol and other drug problems, a key issue impacting health and access to care. This age group has the highest uninsured rates and it is an important health disparities issue. Our conceptual framework is based on a health services and a developmental perspective. Specifically, we examine a multivariate model of individual (demographics and problem characteristics, developmental transitions), treatment (CD services and Continuing Care) and extra-treatment characteristics (family environment, peer environment, 12-step participation) and how they relate to trajectories of alcohol use and related outcomes over 9 years. We also use this model in our analysis of medical service and cost trajectories. We use state-of-the art analytic techniques, including latent growth models, to address specific research questions. Findings from this study have implications for identifying factors important for long-term recovery for youth, for developing targeted intervention programs, and health systems will be able to use findings to develop a continuing care approach to recovery. Findings related to health insurance have significant implications for health reform and policy. PUBLIC HEALTH RELEVANCE: This study is a secondary analysis of a cohort of young adults aged 22-27 who entered chemical dependency treatment as adolescents, and who are now 9 years post treatment. We examine the relationship of important life transitions, lack of health insurance, and health services use, including a Continuing Care model, to long- term trajectories of alcohol use and related outcomes, medical services and cost.